The Rockets have been telling teams for two weeks that they will trade Asik by Thursday, and according to sources close to the process, they gradually continued to move in that direction Wednesday.

ESPN.com reported Tuesday that the Boston Celtics had emerged as the strongest rivals to the Philadelphia 76ers in terms of Asik's likely destination. Entering the final hours before the Rockets' self-imposed deadline, sources said Houston officials spent much of Wednesday weighing the merits of Boston's offer of forward Brandon Bass, guard Courtney Lee and a future first-round draft pick for the 7-footer from Turkey while also remaining engaged in talks with Philadelphia and leaving open the possibility that other teams could still join the bidding.

The Rockets, sources said, have been interested in prying veteran center Spencer Hawes away from the Sixers along with a future first-round pick, but they won't know until Thursday whether Philadelphia is prepared to part with that much for Asik or whether Boston's offer is the best available.

The Boston Herald reported late Wednesday that the Celtics actually made the offer featuring Bass, Lee and a protected first-rounder last week, only for Houston to reject it.

On Thursday, Celtics president of basketball operations Danny Ainge downplayed the notion his team is on the cusp of making a trade, but he acknowledged that the front office staff is having discussions with teams about what is available.

Appearing on Boston sports radio 98.5 the Sports Hub, Ainge was asked if any deal was imminent.

"I have no indication of that, other than the rumors," Ainge said. "I have no indication, in my dealings with and calls with other teams, that we're close to doing a deal."

When this process began, Rockets officials were hopeful of getting more for Asik, who is regarded as one of the league's elite interior defenders. But the combination of Asik's offensive limitations and a $15 million balloon payment next season in the final year of his contract appears to have made it difficult for Houston to generate the interest it anticipated.

When ESPN.com first reported Dec. 6 that the Rockets were telling teams they planned to trade Asik by Dec. 19, one of the reasons used to explain Houston's deadline was the fact that Thursday is the last day any traded players can be packaged with other players in a subsequent trade before the league's Feb. 20 deadline. The immediate decision for Houston, then, is whether it's better to go ahead with the best available offer Thursday to retain maximum flexibility or whether it's smarter to step away from the bargaining table and reset in hopes of getting a better deal.

Sources said the quality of the draft pick that the Celtics are willing to surrender from their stash of nearly 10 future first-rounders over the next half-decade will be a key factor in determining whether the proposed Asik-to-Boston deal goes through.

Many sources connected to the talks, however, expressed belief Wednesday that the Rockets ultimately will go through with a trade, since Asik's demotion from the starting lineup and desire to be dealt following Dwight Howard's arrival in July have hung over the team for the past month.

The Rockets will have a better chance of getting a trade construction they like if a third team can be recruited as a facilitator, but sources said Wednesday that the Atlanta Hawks and Cleveland Cavaliers -- two teams widely anticipated to be at the heart of the Asik talks -- were not engaged in active negotiations with Houston.

The Hawks, sources said, have been resistant to making versatile forward Paul Millsap available to the Rockets, while Cleveland's interest was said to be as a potential third team to absorb the contract of Celtics forward Jeff Green. But sources say Boston has refused to make Green available in Asik scenarios, offering Bass instead.

Both Bass and Lee played with Howard in Orlando, but there are questions about how well Bass' game meshes with Howard's compared to power forwards with better shooting range. On the plus side, Bass has only one season left on his contract after this one at $6.9 million.

There are league sources, meanwhile, who have maintained all month that the Rockets' plan to trade Asik by Dec. 19 was hatched in part because of general manager Daryl Morey's confidence in being able to strike a deal with Philadelphia, where former Rockets assistant general manager Sam Hinkie is now running the Sixers' front office.

The combination of a thigh injury that led to knee discomfort and Asik's clear frustration since being dropped from Houston's starting five in mid-November has limited him to just eight games since Nov. 20, with stints ranging from seven to 23 minutes in those appearances off the bench behind Howard.

Houston tried playing Howard and Asik together and initially was hesitant to entertain trade offers for the 27-year-old, based on the premise that the luxury of having either Howard or Asik on the court at all times was too valuable to surrender so quickly. But Asik's angry reaction to losing his starting spot changed the dynamic.

Asik has wanted a new address from the moment Howard arrived in July and, according to sources, has privately requested a trade numerous times in the months since.

He started his first 90 games as a Rocket after signing as a free agent in the summer of 2012 before declaring himself unavailable to play the Knicks in New York on Nov. 14, snapping a streak of 239 consecutive games played in the regular season. Asik is averaging 18.3 minutes per game, down from last season's career high of 30.3, and is averaging just 4.4 points and 6.8 rebounds.